Optimised performance of the backward longswing on rings

Abstract

Many elite gymnasts perform the straight arm backward longswing on rings in competition. Since points are deducted if gymnasts possess motion on completion of the movement, the ability to successfully perform the longswing to a stationary final handstand is of great importance. Sprigings et al. (1998) found that for a longswing initiated from a still handstand the optimum performance of an inelastic planar simulation model resulted in a residual swing of more than 3° in the final handstand.

For the present study, a three-dimensional simulation model of a gymnast swinging on rings, incorporating lateral arm movements used by gymnasts and mandatory apparatus elasticity, was used to investigate the possibility of performing a backward longswing initiated and completed in handstands with minimal swing. Root mean square differences between the actual and simulated performances for the orientations of the gymnast and rings cables, the combined cable tension and the extension of the gymnast were 3.2°, 1.0°, 270 N and 0.05 m respectively.

The optimised simulated performance initiated from a handstand with 2.1° of swing and using realistic changes to the gymnast's technique resulted in 0.6° of residual swing in the final handstand. The sensitivity of the backward longswing to perturbations in the technique used for the optimised performance was determined. For a final handstand with minimal residual swing (2°) the changes in body configuration must be timed to within 15 m s while a delay of 30 m s will result in considerable residual swing (7°).

Introduction

Judging criteria for the rings event in Men's Artistic Gymnastics stipulate that elite gymnasts must perform backward and forward swinging elements completed in stationary handstand positions to score highly in competition (F.I.G., 1997). The straight arm backward longswing (Fig. 1) fulfils these requirements and consequently is performed by many elite gymnasts. However, if a gymnast possesses appreciable motion in the final handstand, points are deducted, and a lower score is given for the routine. The ability to perform a backward longswing to a stationary handstand is therefore of great importance to elite gymnasts.

Previous studies of longswings have used two-dimensional analyses to identify differences in cable tension patterns between elite and non-elite gymnasts (Nissinen, 1983), to calculate net forces at the shoulders (Brüggemann, 1987) and to estimate resultant hip and shoulder torques (Sprigings et al., 2000). From observations (Fig. 1), however, it is clear that elite gymnasts make use of extensive lateral arm movements during the descending (b–d) and ascending (f–h) phases of the longswing, indicating that three-dimensional analysis of the activity is necessary. As a consequence, the previous two-dimensional studies may provide only limited insight into the performance of a backward longswing to still handstand.

In a recent simulation study, Sprigings et al. (1998) developed a three-segment planar model to investigate the potential problem of removing unwanted swing in a handstand when performing a backward longswing. By varying the gymnast's technique and the initiation of the longswing with respect to the angle of the rings cables from the vertical, an initial handstand displaying 10° of swing-amplitude was reduced to 1.5° swing in the final handstand. Furthermore, the study found that when commencing the longswing from a stationary handstand, the model could not produce a final handstand with less than 3° residual swing.

This raises the question of whether the residual swing can theoretically be reduced to zero using a sufficiently detailed simulation model. If this is so and a gymnast should be able to produce zero residual swing using perfect technique and perfect timing then what are the practical limits of performance? This paper will address these two questions using a three-dimensional model of a gymnast and rings apparatus incorporating elastic structures.